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The signal sequence receptor (SSR) is a glycosylated endoplasmic reticulum membrane receptor related with protein translocation across the ER membrane. The SSR consists of 2 subunits, a 34-kD glycoprotein (alpha-SSR or SSR1) and a 22-kD glycoprotein (beta-SSR or SSR2). The human beta-signal sequence receptor gene (SSR2) maps to chromosome bands 1q21-q23. Diseases correlated with SSR2 include calcaneonavicular coalition, and osteosarcoma, and among its related super-pathways are Viral mRNA Translation and Generic Transcription Pathway.

The signal sequence receptor (SSR) is a glycosylated endoplasmic reticulum membrane receptor related with protein translocation across the ER membrane. The SSR consists of 2 subunits, a 34-kD glycoprotein (alpha-SSR or SSR1) and a 22-kD glycoprotein (beta-SSR or SSR2). The human beta-signal sequence receptor gene (SSR2) maps to chromosome bands 1q21-q23. Diseases correlated with SSR2 include calcaneonavicular coalition, and osteosarcoma, and among its related super-pathways are Viral mRNA Translation and Generic Transcription Pathway.

Prosaposin (PSAP) is a precursor of 4 lysosomal saposin proteins (saposin A, B, C and D). Saposins are heat-stable glycoproteins which facilitate the catabolism of glycosphingolipids with short oligosaccharide groups. PSAP stimulates neurite outgrowth and increases choline acetyltransferase activity. Prosaposin exists both as a secretory protein and as an integral membrane protein and has neurotrophic activities. The secreted prosaposin is assumed to have additional functions in human milk, cerebrospinal fluid and seminal plasma. PSAP gene mutations are linked with Gaucher disease, Tay-Sachs disease, and metachromatic leukodystrophy.

PC4 and SFRS1 Interacting Protein 1 (PSIP1) is a transcriptional coactivator involved in neuroepithelial stem cell differentiation and neurogenesis. PSIP1 is also involved particularly in lens epithelial cell gene regulation and stress responses. PSIP1 has a significant role in lens epithelial to fiber cell terminal differentiation. In addition, PSIP1 plays a protective role during stress-induced apoptosis. Furthermore, PSIP1 is a cellular cofactor for lentiviral integration.

Since April 2012, cases of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) have been identified in various countries. Coronaviruses are the cause of the common cold, SARS (severe acute respiratory syndrome) and other severe illnesses with high mortality rates, all are classified into coronavirus family. MERS-CoV is a new type of SARS found in the coronavirus family causing severe pneumonia with sudden and serious respiratory illness with high mortality rates as well. Since January 27th 2015, the WHO has reported 956 human cases, including 351 deaths. More cases of the new coronavirus strain are expected. Like in other coronaviruses, large surface spike glycoprotein is a central structural protein of this virus; it is located above the virion surface to bind and enter into the target cell. Spike protein has 2 domains- S1 and S2. The S1 domain is responsible for cellular tropism and interaction with target cell, while the S2 domain is responsible for membrane fusion. The C-terminal of S1 domain contains a receptor binding domain, and is also a potential target for vaccine development and an antigen for diagnosis.

Methionine sulfoxide reductase B (MsrB) from Escherichia coli is a member of the msrB Met sulfoxide reductase family. The E.coli msrB carries out the reduction of methionine-R-sulfoxide to methionine. msrB possess a metal binding site composed of 2 CXXC motifs. The bound metal (zinc or iron) may stabilize the conformation of the enzymes.

SNRPB is one of several nuclear proteins which are found in common among U1, U2, U4/U6, and U5 small ribonucleoprotein particles (snRNPs). These snRNPs are involved in pre-mRNA splicing, and the SNRPB protein may also have a role in pre-mRNA splicing or snRNP structure. SNRPB binds to the downstream cleavage product (DCP) of histone pre-mRNA in a U7 snRNP dependent manner. SNRPB functions in the U7 snRNP complex which is involved in histone 3'-end processing.

Serine/arginine-rich splicing factor 1 (SFRS1) belongs to the arginine/serine-rich splicing factor protein family, and functions in both constitutive and alternative pre-mRNA splicing. SFRS1 binds to pre-mRNA transcripts and components of the spliceosome, and can either initiate or inhibit splicing depending on the position of the pre-mRNA binding site. The ability of SFRS1 to activate splicing is controlled by phosphorylation and interactions with other splicing factor associated proteins.

Fibrinogen silencer-binding protein (FSBP), interacts with X11alpha. The X11alpha/FSBP complex send signals to the nucleus in order to repress glycogen synthase kinase-3beta promoter activity. X11alpha is a neuronal adaptor protein that interacts with the amyloid precursor protein (APP) via a centrally located phosphotyrosine binding domain to inhibit the production of Abeta peptide that is deposited in Alzheimer's diseased brains.

S100b is a member of the S100 family of proteins which are a family of EF-hand calcium binding proteins that exist mostly as dimers of the 20 currently identified individual S100 monomers. The S100B homodimer is expressed in cells of the central nervous system, glial cells and in certain peripheral cells e.g. Schwann cells, melanocytes, adipocytes and chondrocytes. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. S100 proteins are involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21; however, S100b is located at 21q22.3. The determination of S100B in serum levels may be used to monitor the extent of brain injury and malignant melanoma. S100b proteins may have a role in Neurite extension, proliferation of melanoma cells, stimulation of Ca2+ fluxes, inhibition of PKC-mediated phosphorylation, astrocytosis and axonal proliferation, and inhibition of microtubule assembly. Chromosomal rearrangements and altered expression of the S100b gene are implicated in several neurological, neoplastic, and other types of diseases, including Alzheimer's disease, Down's syndrome, epilepsy, amyotrophic lateral sclerosis, melanoma, and type I diabetes.

SDF-1 (stromal cell-derived factor-1) is small cytokine belonging to the chemokine family that is officially designated Chemokine (C-X-C motif) ligand 12 (CXCL12). It is produced in two forms, SDF-1?/CXCL12a and SDF-1?/CXCL12b, by alternate splicing of the same gene. Chemokines are characterized by the presence of four conserved cysteines, which form two disulfide bonds. The CXCL12 proteins belong to the group of CXC chemokines, whose initial pair of cysteines are separated by one intervening amino acid. CXCL12 is strongly chemotactic for lymphocytes and has been implicated as an important cell co-ordinator during development. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. As another role, CXCL12a alters also the electrophysiology of neurons. CXCL12 was shown to be expressend in many tissues in mice (including brain, thymus, heart, lung, liver, kidney, spleen and bone marrow).
The receptor for this chemokine is CXCR4, which was previously called fusin. This CXCL12-CXCR4 interaction used to be considered exclusive (unlike for other chemokines and their receptors), but recently it was suggested that CXCL12 is also bound by CXCR7 receptor.
The gene for CXCL12 is located on human chromosome 10. In human and mouse both CXCL12 and CXCR4 show high identity of sequence: 99% and 90%, respectively.

HBsAg is the surface antigenof the Hepatitis-B-Virus (HBV). The capsidof a virus has different surface proteins from the rest of the virus. The antigen is a protein that binds specifically on one of these surface proteins. It is commonly referred to as the Australian Antigen.

SPG21 binds to the hydrophobic C-terminal amino acids of CD4 which take part in suppression of CD-4 dependant T cell activation. The interaction with CD4 is mediated by the noncatalytic alpha/beta hydrolase fold domain. SPG21 adapts the stimulatory activity of CD4. SPG21 is broadly expressed in diverse tissues including heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. Mutations in SPG21 cause Mast syndrome, an autosomal-recessive complicated form of hereditary spastic paraplegia characterized by dementia, thin corpus callosum and white matter abnormalities.

PSMA is a cancer antigen that is widely expressed as a noncovalent homodimer on the surface of prostate cancer cells, rather than on normal cells, therefore it is an interesting target to image prostate tissues when being used with radioactive antibodies. PSMA is expressed on the surface of novel blood vessels that nourish a broad range of other solid tumors. PSMA is a type II membrane protein with folate hydrolase activity produced by prostatic epithelium. PSMA expression is found in extraprostatic tissues, including small bowel and brain.

Glycoprotein Nmb (GPNMB) is a member of the PMEL/NMB family. GPNMB is a type I transmembrane glycoprotein which exhibits homology to the pMEL17 precursor, a melanocyte-specific protein. GPNMB is expressed in the lowly metastatic human melanoma cell lines and xenografts but has no expression in the highly metastatic cell lines. GPNMB might be involved in growth delay and reduction of metastatic potential. GPNMB is up-regulated in a number of cancer cells, including in glioblastoma multiforme. GPNMB is expressed in many melanoma cells, as well as in tissue macrophages, including liver Kuppfer cells and lung alveolar macrophages, in podocytes and in some cells of the ciliary body of the eye (at protein level). GPNMB is hardly detectable in the healthy brain.

Persephin is a member of the GDNF ligand subfamily of the TGF-beta superfamily. PSPN encourages the existence and growth of key dopaminergic and motor neurons, as well as taking part in kidney development. Nonetheless, persephin does not support existence of peripheral neurons.

SNUPN is a nuclear import adaptor protein which is part of the Snurportin family.
SNUPN is Localized to the cytoplasm and nucleus and contains an N-terminal IBB domain and a trimethylguanosine (m3G)-cap binding domain. SNUPN binds specifically the terminal 2,2,7-m3G-cap at the 5'' end of U snRNPs and is involved in transport of U snRNPs into the nucleus through an association with Importin β.

Single-Stranded DNA Binding Protein 1 (SSBP) participates in mitochondrial biogenesis. SSBP binds preferentially and cooperatively to ss-DNA. The SSBP protein is involved in mitochondrial DNA replication and associates with mitochondrial DNA.

S100b is a member of the S100 family of proteins which are a family of EF-hand calcium binding proteins that exist mostly as dimers of the 20 currently identified individual S100 monomers. The S100B homodimer is expressed in cells of the central nervous system, glial cells and in certain peripheral cells e.g. Schwann cells, melanocytes, adipocytes and chondrocytes. S100 proteins are localized either in the cytoplasm or the nucleus of a wide range of cells. S100 proteins are involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. There are at least 13 members in the S100 gene family, which are located as a cluster on chromosome 1q21; however, S100b is located at 21q22.3. The determination of S100B in serum levels may be used to monitor the extent of brain injury and malignant melanoma. S100b proteins may have a role in Neurite extension, proliferation of melanoma cells, stimulation of Ca2+ fluxes, inhibition of PKC-mediated phosphorylation, astrocytosis and axonal proliferation, and inhibition of microtubule assembly. Chromosomal rearrangements and altered expression of the S100b gene are implicated in several neurological, neoplastic, and other types of diseases, including Alzheimer's disease, Down's syndrome, epilepsy, amyotrophic lateral sclerosis, melanoma, and type I diabetes.

Phospholipid Scramblase 3, (PLSCR3) may mediate accelerated ATP-independent bidirectional transbilayer migration of phospholipids upon binding calcium ions which results in a loss of phospholipid asymmetry in the plasma membrane. PLSCR3 may play a key role in the initiation of fibrin clot formation, in the activation of mast cells and in the recognition of apoptotic and injured cells by the reticuloendothelial system. In addition, PLSCR3 seems to play a role in apoptosis, through translocation of cardiolipin from the inner to the outer mitochondrial membrane which promotes BID recruitment and enhances tBid-induced mitochondrial damages. Among the diseases associated with PLSCR3 are brain ischemia, and ischemia.

HSPB7 is part of the Heat shock protein beta family. The HSPB family is one of the more diverse families within the group of HSP families. Several members have chaperone-like activities and/or participate in cytoskeletal stabilization. Several members also show a dynamic, stress-induced translocation to SC35 splicing speckles. HSPB7 constitutively localized to SC35 splicing speckles, determined by its N-terminus. HSPB7 does not support refolding though HSPB1 and HSPB5 chaperone heat unfolded substrates and keet them folding competent.

The heat-shock response is elicited by exposure of cells to thermal and chemical stress and through the activation of HSFs (heat shock factors) results in the elevated expression of heat-shock induced genes. Heat shock factor binding protein-1 (HSBP1), is a 76-amino-acid protein that binds to heat shock factor 1(HSF1), which is a transcription factor involved in the HS response. During HS response, HSF1 undergoes conformational transition from an inert non-DNA-binding monomer to active functional trimers. HSBP1 is nuclear-localized and interacts with the active trimeric state of HSF1 to negatively regulate HSF1 DNA-binding activity. Overexpression of HSBP1 in mammalian cells represses the transactivation activity of HSF1. When overexpressed in C.elegans HSBP1 has severe effects on survival of the animals after thermal and chemical stress consistent with a role of HSBP1 as a negative regulator of heat shock response.